When using tabbed shells, it would be very useful to get some sort of
notification of a beep in a tab. konsole implements this by changing the icon
for that tab from a terminal to a bell and only changes it back when you have
pressed a key in that tab. konsole also has a notification on the panel for a
second. 

My particular use case for this request is having my irc client in one tab and
working in several others and can tell if someone is trying to talk to me on irc
by looking at the icon for that tab, rather than constantly checking back or
neglecting irc completely.